Alternating current operated radio set



Mgrch 22, 1932. NYMAN 1350,270

ALTERNATING CURRENT OPERATED RADIO SET Filed Feb 26, 1926 SOURCE y Ac a,

I IWNToR.

ATTORNEY Patentecl;Mar. 22 1932 ennxannnninnimm, or iTEwlYonx ,-f N;

- COBBQEATIORDENEW YORK, N. x,-

' trontube amplifiers may beoperatedwithout interference from chum of I alternating cur: rent supplied from the usual commercialfal Y., ASSIGNOR T0 DUBILIEI-R CQNDEliTSER ncoRPonATIoN. or DELAWARE .1 fA fLTERrIArING ,cUnR NT OPERATED RADIO sun "macaw filed reb uar fzey 1926; 1 Serial No. 90,807;

invention relatesgbrioadly 0 alter-nah ing: current actuated radio receiving appa rat-us and more particularly to a vcircuit a1"- rangementa whereby the present commercial designs ofreceiving sets employingelectron-v tube=.amplifying systems can be readily 'chan'gedeso that the tube circuits may. be e'f fectively energized by electric power derived fromi-t-hes usual alternating current lighting source. 7 1 I One of the objects of mya'invention isqto provide means: whereby existing construction'saof radio: receiving-sets employing" ele'cterna ting currentihouse 'lig hting-fsystem;

"Anotheriobject of my illVGIltlOIl'lS to provide" a radio' receiving system with detector means which does "not require :the supply: of

alternating current i or 1 voltage and 2 which lSzf not; detrimentally afiected by I the alternatingsqcurrent characteristic f th Power upp ya :LA? furtheriobj ect: offmy invention: is pro-"- vide? a: detector; system for :the signaling energyiof:analternatingcurrent; operated radlo receiver which: is not. influenced byrthe hum] power supply. but

ofthe a'lternat'ingcurrent I g which: functions: to rectify the incom ng s1g-. na lin'ga energy- 1 Stillianothen objectarofl my invention is the several necessary elements comprising my invention may. be varied in construction, proporti on andarrangernent, vwithout departingfrom thespiritand'scope of the appended c a ms V In the Figure? la is; dia, gram maticplane-shcwing the; circuit arrangement of; alternating; current 'operatedjradio remusical sounds faction;

; batteries inradio sets and employ an everceiving set embodying the principles of my invention; i

Fig. 2 is a schematic tunedradio frequency battery actuated radio receiving set and V F ig.;'3 shows a regenerativereceiver system embodying the principles of my invention.

The same numerals and symbols have I been used to identifythe same parts: throughout the several views;

' .Actuation! of [radio receiving sets from an ordinary cycle house lighting supply? cir-- cuit is productive, as is: welll'known; of a very:

pronounced fdisturbing hum that generally" J is not only very-disagreeable to listen; to, but:

also prevents the intelligent? receptionofi the either spoken '.words or Therefore, batteries: have received signals;

been; found up to. the present to be the most practical yreliable and noiseless source of -power for energizing the? filaments amdvthe plate clrcults of: the var ous vacuum? tubes, V servlng assaniplrfiers"or-detectorstin the" re ce'ivers in ordinary use. "Although. battery actua-tedj'radio-sets admittedly are'capable of quiet reception nevertheless; the ,v reliability of? the" battery cells 'is'ifar from being infallr;

plan 'view showing the circuitsiheretofore employedfinla multi-tube' ble; for their active. lengths of; lifexisv usually short,v .owing'to the occurrence" of internalchemical action even. when no. current' isxbeing drawn fromrt-he cells, hence, frequent recharging or rather :costlyf replacement: of cells, is necessary andrcauses; general dissatis- The: ability to] dispense withfall present powersourceinstead is of great :ad-Y Vantagepand various inventors have devised more 0r;less-complicated methods; and means whereby an A..G. supply. mayfbenapplied to certain radio' sets with: a: fair degree: satisfaction; While it'has. been: found feasible to.

employralternating current-directly.applied to all the filaments of the; tubes *of'the set ex cept that 1 of the detector; tube; usually 1 the 9 filamentof; the? latter is 11 supplied with heating current by a'battery of suitable voltage, orthe triode tu'be detector' isi repl aced'iby somefformbf-fcrystal detector; for; when-a I triode electron tube isi'usedlasxa det'ector there ergy collecting circuit; audio frequency transformer T constitute present a plate to which alternating current voltage is supplied.

I have discovered that a photo-electric cell when exposed to light rays will'serve asa stable detector of the signaling current without interference from the alternating hum. I therefore provide an electron tube amplify ing system at the receiver with a photo-elec-- tric cell interposed in the system for deriving unidirectional currents from the incoming signaling energy which may be further amplified through an electron tubesystem which is supplied with power from an alternating current lighting source without interference from the alternating current bum in the responsive device which is actuated by the ant plifying system. r

. Referrlng more particularly to Figure 1 of the drawings the numeral 1 indicates an antenna system forming a radlo frequencyoscillating circuit which is connected to groundat E. Triode vacuum tubes 2 and 3,

and hlgh frequency transformers T T T constitute a high-frequency amplifying system connected with the radio frequency en- Tubes-4e and 5 and the audio frequency amplifying elements of the receiving set to which the customary head phones 6 or inlieu thereof, some form of loud speaker,

are connected in the plate circuit of tube 5. Power for the filaments of tubes 2,13, 7 4 and 5, is supplied from the low voltage secondary of tie. step-down transformer '1, whose primary'winding is connected to the' standard source of alternating current power supply. The filament leads 7, 7 of tubes 2, 3, 4, 5, are connected inparallel across the common leads 8, 9, which are respectively connected with transformer terminals 10, 11, shunted by a non-inductive balancing resistance 12 with a centrally located slider 13.

Plate current'for the triode tubes. of the set is supplied also from the A. (l. mains by any suitable rectifier S, preferably one of the vacuum tube type, which is interposed between the A. G. mains and common leads 14,

15,connected in the plate circuits of the tubes 2, 3, 1, 5. In practice, filament transformer T and rectifying outfit S may be suitably mounted within a protected container or case,

1 that is, provided with the requisite terminal binding posts for making the correct connections to the set. Adjustable'contact. 13

or the slider of'balancing resistance 12, isconnected to the negative lead 1 1 of rectifier S' by wire 16. By suitably adjusting the position of slider 13 on resistance 12 the normal voltage of the grids is kept at a steady value with respect to the average voltage of the electrical midpoint of the filaments thus elim inating any hum which variations of the grid voltage would cause. 1

Between the radio and the audio stages composing the receiving set, photo-electric cell PC is interpolated into the circuit in such fashion that the grid electrodereceives the output-energy ofT Sensitive plate 17 of light cell PC is electrically connected to grid 18 of audio frequency amplifying tube 4 by conductor 19, to which one terminal of a noninductive resistance 20, is also connected. Terminal 21 of resistance 20 is connected by lead 22 to one end of the secondary winding of audio transformer T Resistance terminal 21 is v likewise directly connected to lead 14 or preferably, to a terminal of a biasingbattery C, which may be interpolated between 21 and 14. Positioned between the photo-electric cell PC and facing plate 17 thereof, miniature bulb B is employed to steadily illuminate cell PC with light of the filament are connected. Since photo-cell PC permits only the flow of uni-directional current, whoseintensity varies according to. the voltage applied-to the grid and plate of the cell,; which is continually subjected to the steady illumination of the. adjacentbut sep arate'bulb B, high frequency. voltages ap plied to the grid of cell PC by the secondary oftransformer T produce a uni-directional flow of current of varying intensity through the cell PC which current is passed on to the audio amplifiers 4 and 5 and thus to the phones 6 or other variety of indicator. Photo-cell PC, therefore, performsthe function of a detector, which in contrast with the usual triode detector contains no self-contained hot filament that gives rise to disturbances when it is supplied with alternating heating current. In practice, light cell PC is so constructed thatit can be inserted into'the socket ordinarily occupied by the usual triode detector tube. Luminousbulb B is mounted. in asuitable socketand container which may be: located in proximity to PC in any con venient manner so that the hot cathode 26 tendsfto subject the photo-electric cell to a combination of lightrays.

InFig'ure 2 I have shown the usual battery actuated receiving set employing'tuned T. and T Filament batteries A and plate p by those skilled-in the art batteries B replace in Fig. 2 the A. C. transformer T, and the A. C. rectif ing and smoothing outfit'S of Fig. '1. l articular connections necessary for the installation of light bulb B and detector photo-cell PC in place of the triode detector 27 of Fig.2, are clearly indicated in Fig.1 and the diagrams represent the departure necessary from'the battery operated set in order to excite the tube circuits from alternating current. That is to say, electron tube detector 27 is substituted by the photo-electric cell PC and light bulb B when the supply systemis changed over from batteries to the alternating current source.

In Figure 3 of the drawing I have illustrated a regenerative form of detector circuit constituted by the photo-electric cell PC hav ing an additional electrode 28 therein fconnected through an inductance 29 to the input of a transformer system T which connects to the two stages of audio frequency amplificav tion. The inductance 29 couples with'inductance 30 in the antenna circuitenabling an increased amount of rectified signaling energy to be passed to the amplification system.

Thebulb B is continuously energized for rendering the photo-electric cell conductive to uni-directional current.

The three electrode photofelectric cell shown in Figure 3 can very advantageously be employed in the circuit shown in Figure 2 by substituting it for the middle vacuum tube which has the plate 27." This photo- 5 the place of the plate 27 with-the coil 29 arranged to cooperate with the transformer T While I have shown and described the pre-' ferred form of my invention I wish it to be understood, that I .do not confine'myself to the precise details of construction as herein set forth by way of illustration, as it is apparent that various changes may be made therein without departing from the spirit of the invention or exceeding the scope of the appended claims. What I claim as new and desire to secure by Letters Patent of the follows :1

1. In a signal receiving apparatus, means for connecting said apparatus to a source of alternating current, a plurality of amplifying devices each having an electron emitting element, a photoelectric detecting device having an electron emitting element and means and means for energizing. all of saidelectron gizing circuit adapted to be connected to a source of alternating current, a plurality of electron discharge amplifying devices having their electron emitting elements energized through said circuit, a photoelectric detecting device having an electron emitting element and means for energizing said last named element through said circuit.

In testimony whereof I ,afiix my signature...

' ALEXANDER NYMAN.

electric cell will be so connected that the plate i in the usual United States is as emitting elements throughsaid connecting means. I

2. Signal receiving apparatus comprising a plurality ofelectron discharge tubeshaving heatable electron emitting cathodes, said 

